Julie Morgan AM for Cardiff North
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Julie Morgan MS for Cardiff North

20mph - FAQs

Introducing 20mph speed limits: frequently asked questions


Why have you introduced a 20mph speed limit on residential roads and busy pedestrian streets across Wales?


The evidence from around the world is very clear – decreasing speeds will reduce collisions, save lives and reduce injuries – helping to improve the quality of life and make our streets and local communities safer for all.

A public health study estimated that the 20mph default speed limit could result – every year - in:

  • 40% fewer collisions
  • 6 to 10 lives lives saved
  • 1200 to 2000 people avoiding injury


The change will also:

  • make streets safer for playing, walking and cycling
  • encourage more people to walk, wheel or cycle
  • makes our communities safer
  • improve health and wellbeing
  • reduce noise pollution

The legislation was approved by the Senedd in July 2022.


Why have you made this blanket change?


The change is not ‘blanket’. These changes will affect most 30mph roads, but not all.


The law changes the default speed limited on restricted roads. These are usually residential or busy pedestrian streets with streetlights. 


The Welsh Government provided local authorities with guidance to help them to choose which of their roads should remain at 30mph. [link to https://www.gov.wales/setting-exceptions-20mph-default-speed-limit-restricted-roads]


The Welsh Government has published a map on DataMapWales that shows which roads will stay at 30mph. [link to https://datamap.gov.wales/maps/roads-affected-by-changes-to-the-speed-limit-on-re/]


How much is this change costing?


The introduction of the 20mph speed limit costs £29million.


This cost is outweighed by the casualty prevention savings, including the reduced impact on NHS and emergency services. One public health study estimates these savings could be up to £92m every year. And that’s without considering the wider health benefits of people walking and cycling more.



Why do people say this change will cost the economy £4.5 billion?


The Welsh Government’s assessment shows that reducing speeds to 20mph can result in an average increase of one minute per journey, 9 lives saved and 98 serious injuries prevented each year.


Before the law was passed, an impact assessment was produced that considered all the potential costs. This was included in the explanatory memorandum [link to https://business.senedd.wales/mgIssueHistoryHome.aspx?IId=39677 ].


It included the costs of any delays to travel time. The method used is now under academic debate for its effectiveness when calculating small delays.


So, the estimated cost to the economy of £4.5 billion over 30 years may not be an accurate reflection of the true cost.


The slightly longer travel time was the only negative economic impact identified.


It is estimated that the casualty prevention savings, including the reduced impact on NHS and emergency services, could be up to £92m every year.



What was learnt from the 20mph trial areas?


A default 20mph speed limit was trialled in 8 areas. These were: 

  • Abergavenny and Severnside, Monmouthshire
  • North Cardiff
  • Buckley, Flintshire
  • Cilfrew Village, Neath and Port Talbot
  • St Dogmaels, Pembrokeshire
  • St Brides Major, Vale of Glamorgan
  • Llanelli North, Carmarthenshire


You can read the first monitoring report detailing some of the impacts introduction of 20mph has had in these communities. Overall speed has reduced in these areas.


The most significant positive behaviour changes were observed in St Brides Major and St Dogmaels. People travelling at or below 24mph in St Brides Major has increased from 23% to 45% following the introduction of 20mph. And in St Dogmaels there has been an increase from 54% to 84%.


Research shows that each 1mph slower people drive in urban areas, reduces the number of collisions by an average 6%.


The next monitoring report is expected to be published by the end of 2023.


Will the 20mph speed limit be enforced?


The Police and GoSafe will enforce 20mph, like any other speed limit, to make our roads safer for all users. They will also be engaging with motorists to ensure that the new speed limits are respected.



This is just a money-making scheme for Welsh Government, isn’t it?


No. This is a road safety scheme.


Initially there will be an engagement approach for drivers who are driving just over the limit. More information on this can be found here: GoSafe - 20mph Enforcement [link to: https://www.gosafe.org/campaigns-and-operations/20mph/]


People who are caught speeding significantly over 20mph, as with any other speed limit, will risk a fine and points on their license.


The money generated by 20mph speeding fines, as with all speeding fines, is directed HM Treasury. Welsh Government do not receive any monies from speeding fines.


Why are the Fire Service involved in 20mph enforcement events?


As the Fire and Rescue Service attend more calls to road traffic collisions than house fires, they have a dedicated road safety team. These teams are not involved in callouts to emergencies and aim to inform drivers about the consequences of collisions caused by speeding.


Having seen the results of many collisions, they are well placed to engage drivers and are involved in this aspect of the 20mph roll-out.



Won’t 20mph prevent emergency services from getting to emergency calls on time?


Police, fire and ambulance services are allowed by law to exceed speed limits to respond to emergency calls. The introduction of the 20mph default speed limit does not change that and so should not delay their response.


The police believe response times will not be affected and that the roads being slower could make it easier for emergency services to make progress.


20mph will cause more congestion, won’t it?


It isn’t believed that a 20mph speed limit will increase congestion or the number of vehicles driving on the road.


This is supported by evidence from Spain that have brought in 20mph or similar default speed limits.


20mph isn’t in the Highway Code. I’ll keep driving according to that.


The Highway Code is being updated online on 17 September to reflect the 20mph speed limit in Wales.


The driving theory and practical tests have also been amended by the DVSA.


Why are you bringing this in when no-one supports it?


Most people in Wales (63%) support a lower speed limit where people live. [link to https://www.gov.wales/20mph-public-attitudes-research ]


The law was also passed by the majority of the Senedd.


How will a lower speed limit promote walking and cycling?


Lower speeds mean that people feel more comfortable to walk and cycle and it is safer for children to walk to school. Older people, disabled people or people with additional needs will feel more able to travel independently.


There is evidence from across the world that vehicle speeds are one of the main reasons why people do not walk or cycle or do not allow their children to walk or cycle to school.


Will slower speed increase air pollution?


Imperial College found that 20mph limited areas were “pollution neutral”. Many things contribute to pollution levels. They include:

  • driving style,
  • acceleration,
  • braking,
  • vehicle condition
  • distance travelled and
  • engine temperature.


The Welsh Government believes the lower speed limits will encourage more people to choose active ways to travel and there will be fewer polluting cars on the roads.


How do slower speeds increase safety?

The World Health Organisation states that the most effective way to improve pedestrian safety is to reduce the speed of vehicles.


In 2022, police force figures indicate that 51% of collisions happened on 30mph roads [link: https://www.gov.wales/police-recorded-road-collisions-interactive-dashboard )].


A Transport for London report shows that since 20mph limits were introduced on key roads in London in 2020:


·       the number of overall collisions reduced by 25%

·       Collisions involving vulnerable road users decreased by 36%

·       collisions involving people walking decreased by 63%

·       collisions resulting in death or serious injury reduced by 25%.


By reducing the default speed, it will make it easier for drivers to stop in time to prevent collisions.


In the distance a 20mph car can stop, a 30mph car will still be doing 24mph.


A person is around five times more likely to be killed when hit by a vehicle travelling at around 30mph than they are from a vehicle travelling around 20mph.


What effect will the speed limit have on journey times?


Journey times on roads in urban areas tend to be determined by junctions and signals, rather than the speed limit.


In many cases lowering the speed limit to 20mph will have little or no impact on journey times. Where there is an impact, our analysis showed us that the average journey would only be around 1 minute longer but this would make the roads safer for pedestrians and cyclists.


Why can’t the 20mph limit be only used around schools?


Introducing a 20mph default speed limit will make children safer from the moment they leave home – regardless of where they are going and keeps them safe – inside and outside of school hours.


A 20mph speed limit outside the school won’t protect children for the whole journey as they walk or cycle from home, it would only protect them near the school.


But it won’t just protect children. This change is designed to make streets safer for all of us.


Will all the road signs be in place for 17 September?


20mph signs will no longer be needed on roads where the default is now 20mph. Speed limit signs will be in place where the speed limit changes.


Not all signs will be changed on 17 September, but local authorities are working hard to get all the signs in place as soon as they can.

20 mph zones outside schools can stay in place for up to 12 months, as can any 20mph repeater signs. Any 20mph signs painted onto road surfaces can remain for up to 5 years. Highway Authorities can choose to remove them before these deadlines if they choose to.


Will the roll out involve money being spent on speed bumps?


There is no plan to include traffic calming (including speed bumps) as part of the change to speed limits. There are other ‘softer’ measures that might be introduced, such as using buffer speed limits, removing the centre line, narrowing the carriageway visually, using planting etc.


Will reducing speeds to 20mph damage my car?


Modern cars can drive at 20mph without damaging the engine or components. 


Spain brought in a default 30KMph (19mph) speed limit in urban areas in 2021. They have not seen evidence of any vehicle damage from driving at the new default limit.


Will driving at 20mph mean I use more fuel?


No. Fuel consumption is mainly influenced by the way we drive – driving at a consistent speed is better than stopping and starting.


Accelerating up to 30mph can take twice as much energy as speeding up to 20mph.


A default 20 mph limit and a smooth driving style, can help avoid unnecessary speeding up and slowing down, saving fuel.


Why are bicycles allowed to overtake me when I am driving at 20mph?


Speed limits in the Road Traffic Regulations and the Highway Code apply to motor vehicles only and not to bicycles.


The Highway Code has been updated to include 3 new rules about the new ‘hierarchy of road users’.

The hierarchy places those road users most at risk in the event of a collision at the top of the hierarchy. It does not remove the need for everyone to behave responsibly.

It’s important that all road users:

·       are aware of The Highway Code

·       are considerate to other road users

·       understand their responsibility for the safety of others



Where else have 20mph speed limits been introduced?


There are 20mph speed limits in many cities in England.


There are plan to introduce 20mph across Cornwall and in Scotland and more rural authorities are introducing larger scale extended 20mph programmes, and it has announced that it plans for 20mph to become the norm in built-up areas.


This means up to 28 million people in the UK will live in local authorities where 20mph is normal.


Spain introduced a 30KMph limit (approx. 19mph) for single carriageways in urban areas in 2021. Figures from 2022, show that the number of pedestrians killed in these areas has reduced by 13% compared to pre-pandemic figures.

30KMph and 20mph limits are being introduced across the world including in:

·       Spain

·       France

·       Italy

·       Finland

·       Germany

·       Ecuador

·       England

·       Scotland